That sounds like a good plan Scott...
Don't know about these later OD's, but the 1930's & '40s units would "Freewheel" when the OD was engaged - this means that when coasting, a series of over-running clutch rollers prevents the driveshaft from driving the engine; in other words, you lose your compression-braking benefit when in OD.
When you pull the lock-out cable, the OD is locked-up in direct drive, and all should be fine for your hauling chores.
Good luck...of all the vehicles that would've benefitted from an OD option, the six-cylinder Chevy cars and trucks from '30s thru '54 would've benfitted most; sadly Chevy didn't begin offering OD until the small-block era, when the need for one was disappearing.
Ford owner could at least opt for a Columbia 2-speed rear; I've never heard of such for a Chevy (or Buick, as long as we're talking torque-tubes...)
Good luck with your project!
